The present invention relates to the fabrication of hard porous catalytically active bodies particularly suited as filter media, substrates and/or as catalytic converters for liquids and gases. These bodies may be advantageously used in oxidizing, or in the alternative, reducing environments, and in thermally and mechanically stressful environments. The bodies are prepared by sintering together metal particles, which are an intermix of catalytic metal precursors and structural metals and/or alloys thereof Ceramic structural materials may also be advantageously mixed with the metal particles to produce similar benefits A preferred embodiment of the invention comprises the extrusion of metal particles into porous honeycomb structures that can perform as filters and selectively, catalytically convert noxious exhaust gases into their innocuous states The inventive compositions are directed to be particularly advantageous in the exhaust stream of organically fueled power plants, internal combustion engines, and when used as filters, diesel particulate filters and molten metal filters.
Common to the combustion of organically fueled power plants are the resultant waste NOx and SOx gases. These gases, variously derived, have been accused of ultimately causing pollution problems related to acid rain. In order to abate the widespread effects of NOx and SOx gases, catalytically active substrates are proposed as a remedy for this pollution problem. Generally, the substrate of choice has been a ceramic which is capable of being extruded, can withstand thermal and mechanical shocks, and is capable of being joined with metal oxides that exhibit catalytic activity toward NOx or SOx.
In U.S. Pat. No. 4,758,272, filed May 27, 1987 by K. D. Pierotti and R. R. Wusirika under the title POROUS METAL BODIES herein incorporated by reference as filed, is disclosed a porous metal body comprised of an iron and aluminum alloy composition. The body is extruded from metal powders, formed into a substrate, and subsequently sintered to form a hard porous structure. The resultant product is not catalytically active, but must be joined with a catalyst to provide a catalytic surface for gases and liquids.
Therefore, the primary objective of the present invention was to prepare a porous metallic or ceramic body exhibiting catalytic activity when contacted with gas and/or fluid effluents. A more specific objective of the present invention was to prepare a porous metallic or ceramic body capable of catalytically converting noxious exhaust gases from organically fueled power plants and exhaust gases from internal combustion engines, into their innocuous states.